Alpha-Frequency Stimulation Enhances Synchronization of Alpha Oscillations with Default Mode Network Connectivity.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Brain Oscillations
• Functional Connectivity

Background:

• Alpha (8-12 Hz) oscillations and the default mode network (DMN) are dominant intrinsic brain activities.
• Both alpha oscillations and DMN activity are crucial for spatiotemporal brain organization.
• Dysregulation of alpha and DMN is implicated in various neuropsychiatric disorders.

Purpose of the Study:

• To investigate the mechanistic relationship between alpha oscillations and DMN activity.
• To examine the effect of alpha-frequency transcranial alternating current stimulation (α-tACS) on the coupling between alpha power and DMN connectivity.

Main Methods:

• Simultaneous electroencephalogram-functional magnetic resonance imaging (EEG-fMRI) was employed.
• Data were acquired before and after α-tACS.
• Analysis focused on dynamic coupling between spontaneous alpha power fluctuations and DMN connectivity.

Main Results:

• α-tACS significantly tightened the dynamic coupling between alpha power and DMN connectivity, particularly in the posterior DMN.
• No significant changes were observed for other oscillatory frequencies or major brain networks.
• These findings suggest an inherent coupling between alpha oscillations and DMN activity.

Conclusions:

• The study provides evidence for an inherent mechanistic link between alpha oscillations and the DMN.
• α-tACS effectively modulates DMN connectivity.
• This highlights the potential clinical utility of α-tACS for targeting the DMN in neuropsychiatric conditions.